1. First you will need to navigate to your Admin Dashboard. Select the Inventory Tab and “check all” as shown in the image.
1.5 For the initial import, limit your search to those items with a Quantity between 1-100. You can go back later to change all of the products you do not currently have in your inventory since you won’t be selling any of them.
2. Select the export search results to CSV.
3. Look in the Notifications tab in the upper right corner of your dashboard to select the File Reports.
4. Confirm the file is being generated. You will need to click “Refresh” and or wait for the file to be generated.
5. Once CSV is generated, it will display this message on the right, with the file size.
6. Once you download the CSV file, open it up with your choice of Spreadsheet editor. Ie Excel, Google Sheets, Libre Office Calc, etc. Remove all columns other than “Product Name” and “Category” and then add column Headers for “GST Exempt”, “PST Exempt”, and “HST Exempt”.
Then you will need to enter “Yes” or “No” into each field for each Product row as it applies to your location and product type. See the image below for an example of how it should look.
7. Once you have made the necessary changes to the CSV file, Save it.
8. Once it is ready, navigate to the Admin Dashboard Inventory Mass Create Tab and ensure the “This import has multiple categories” box is checked.
9. On step 3 “Import your File” Ensure the “Match products in this import by category and name” is selected. And under Mode Make sure “Only Update Products” is selected to avoid creating duplicate products.
10, Once the import is complete, check items in your inventory to make sure they are showing the correct tax settings.
http://help.crystalcommerce.com/en/articles/1408757-how-to-export-inventory-to-a-csv-file
http://help.crystalcommerce.com/en/articles/1296813-inventory-mass-create-tab-overview